From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <dev-bounces@dpdk.org> Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 5E2E9A0C41; Wed, 6 Oct 2021 18:28:27 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 4C75C411A6; Wed, 6 Oct 2021 18:28:27 +0200 (CEST) Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [217.70.183.197]) by mails.dpdk.org (Postfix) with ESMTP id AA45441179 for <dev@dpdk.org>; Wed, 6 Oct 2021 18:28:26 +0200 (CEST) Received: (Authenticated sender: blp@ovn.org) by relay5-d.mail.gandi.net (Postfix) with ESMTPSA id 0C19F1C0003; Wed, 6 Oct 2021 16:28:24 +0000 (UTC) Date: Wed, 6 Oct 2021 09:28:21 -0700 From: Ben Pfaff <blp@ovn.org> To: Ferruh Yigit <ferruh.yigit@intel.com> Cc: dev@dpdk.org, Xiaoyun Li <xiaoyun.li@intel.com> Message-ID: <YV3OpSn38Odg8kzw@ovn.org> References: <20210910175733.1248739-1-blp@ovn.org> <fa5f879f-2e6b-81ca-d2bd-6801ed5e0168@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <fa5f879f-2e6b-81ca-d2bd-6801ed5e0168@intel.com> Subject: Re: [dpdk-dev] [PATCH] app/testpmd: Document what the application does. X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org Sender: "dev" <dev-bounces@dpdk.org> On Tue, Sep 14, 2021 at 08:58:31AM +0100, Ferruh Yigit wrote: > On 9/10/2021 6:57 PM, Ben Pfaff wrote: > > I could not find anything in the documentation that says what > > testpmd does. This should save other people time trying to > > figure that out in the future. > > > > Signed-off-by: Ben Pfaff <blp@ovn.org> > > --- > > doc/guides/testpmd_app_ug/run_app.rst | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst > > index 6061674239..7c3406f72b 100644 > > --- a/doc/guides/testpmd_app_ug/run_app.rst > > +++ b/doc/guides/testpmd_app_ug/run_app.rst > > @@ -15,6 +15,12 @@ a list of available EAL command-line options. > > Testpmd Command-line Options > > ---------------------------- > > > > +By default, testpmd receives packets on each configured port and > > +forwards the received packets to its paired port. Ports 0 and 1 are > > +paired, as are ports 2 and 3, and so on. With an odd number of ports, > > +the last port is paired with itself: packets received on the port are > > +sent back out on the same port. > Hi Ben, > > testpmd has the concept of 'forwarding engine' (struct fwd_engine), which is > decoupled from testpmd logic and can be changed in the runtime. What you > described above is the 'io' (default) forwarding engine. > There are forwarding engines like 'flowgen' that generates and send L3 packets, > so behaves like a very simple packet generator, etc... > > And even for the 'io' forwarding engine, the paired port description above is > controlled by "--port-topology=<paired|chained|loop>", so for example if the > 'chained' topology is selected, packets will be forwarded as 0 -> 1 -> 2 -> 3 .. > > > Overall, I understand the intention to briefly describe the testpmd, but I think > it is not correct to reduce the description to packet forwarding, although that > is an important function of testpmd, it is not only function and testpmd does > much more, it has many control path functions. I think that someone who maintains testpmd needs to take this patch over, then. I don't know it well enough.